The separation of trace quantities of Pb, Tl, alkali metals, and alkaline earth metals from concentrated matrices containing other concentrated metal cations, acids, and/or other chemicals is a difficult, but important separation commercially. Industries where such separations are would be advantageous include the semiconductor, nuclear waste cleanup, metals refining, electric power, and other industrial enterprises. The separations are difficult because the metals to be removed are present only in concentrations ranging from parts-per-trillion (ppt) to low parts-per-million (ppm) levels and must be separated from up to several molar concentrations of the matrix chemicals. Hence, a kinetically rapid, highly selective, and strong thermodynamically interactive material is required for the separations.
Articles such as Nakatsuji et al., A New Type of Macrobicyclic Polyether: Synthesis and Complexation of Alkali Metal Cations, Journal of the Chemical Society Chemical Communications, 16, 1045 (1984), and Parsons, Synthesis of Bridged Macrocyclic Polyethers of High Complexing Ability with Group 1a. Salts, J. C. S. Perkin I, 451, (1978), describe three-dimensional molecules containing only oxygen donor atoms with selectivity for and interaction constants with some alkali metal cations and the potential for such with alkali, alkaline earth, Pb, and Tl cations. These molecules are very expensive to produce and have not yet been included in actual separation systems where their properties would be useful.
It would be desirable to formulate oxygen donor polyether macromolecular ligands of this type as well as related oxygen donor macromolecules with improved interaction and selectivity properties into a stable composition whereby the selective properties of the ligands for alkali metal, alkaline earth metal, Pb and Tl cations are maintained in an actual separation system and wherein the ligands can be reused hundreds or thousands of times to make separations. The reuse of such ligands makes their use economical and of significant industrial worth. These objectives are accomplished by means of with the covalent bonding of the appropriate oxygen donor macrocycles via the appropriate attachment arms to hydrophilic inorganic solid supports and the use of such compositions in actual separation processes.